QuickBooks and Microsoft Office are the best examples of this – just about traditional PC software connects to and integrates with them.
In the world of online services this connectivity is even more important. Popular services like Dropbox, Evernote and many others are ensuring dozens and dozens of 3rd party services connect to them and that they connect to others. I wrote about this a few hours ago.
For CRM providers such as Nimble, Batchbook, Infusiosnoft, Act On Software, Zoho, and many more this integration is equally important.
These vendors (Infusionsoft is my employer) must ensure that they are not only a service for contact management and marketing but that they are a PLATFORM and ECOSYSTEM so their customers can use them as launching pads for other business functions.
Also keep in mind that these CRM systems can and should only do so much – they can’t be ALL things to ALL businesses. HENCE, ensure they have a marketplace of 3rd party solutions to bolster and value to their offerings is important.
Nimble recently announced the availability of their API to enable developers to build 3rd party services around Nimble yet connect to their service. It’s not only the API that’s launched but also a Marketplace of integrated products similar to the Google Apps markeetplace, Infusionsoft marketplace or etc.